Various spacecraft and missiles utilize liquid propellants including fuels and oxidizers that are very dangerous. These chemicals can react violently with other materials with disastrous results and can cause serious injury or death to personnel that may come into contact with such chemicals. This serious problem is greatly aggravated by the fact that large quantities of such materials are utilized in spacecraft and missile operations.
The tanks containing such fluids and oxidizers must be periodically filled and drained and such transfers of fluids are high risk operations. These operations involve connecting a suitable valve to an onboard tank on the spacecraft or missile and then opening the valve to permit passage of fluid through the valve and into or out of the onboard tank. Obviously, if a valve leaks during or after such an operation, it could have disastrous results. Consequently, such valves are thoroughly leak tested prior to being put in to operation. However, in spite of such testing, leaks have developed in previous valves during such transfer operations. These leaks have caused serious property damage and injuries to and the deaths of personnel involved in the transfer operations.
In order to help avoid these serious consequences, more than one valve can be utilized so that if one valve fails the other valve will most likely not fail. However, it is possible that several valves will fail even though they have been previously tested for leaks.
This invention overcomes these problems associated with previous valves used in dangerous spacecraft and missile fluid transfer operations and allows such transfer operations to be carried out with minimal risk of dangerous fluid leaks. With this invention, it is possible to leak test each of the redundant valve structures independently just prior to the transfer operation with the valve apparatus in place connected to the onboard tank. If one of the redundant valves fails to pass the independent leak test prior to or after the dangerous fluid transfer operation, appropriate corrective action can be taken so that the defective valve is not placed in service.